1. Field of the Invention
The present invention relates to a photosensitive material processing apparatus in which the dirtying of machinery and non-uniformity of processing solutions due to crystal deposition of processing chemicals are prevented.
2. Description of the Related Art
In photosensitive material processing, i.e., developing processing of photosensitive materials, a photosensitive material is conveyed through and submerged for predetermined times in various types of processing solutions stored within processing tanks in an automatic developer.
Conventionally, such processing of photosensitive materials has been carried out in an open system. However, because the respective concentrations of the processing solutions containing processing chemicals become non-uniform due to the evaporation of moisture from the liquid surfaces, processing apparatuses having various types of evaporation preventing means have been proposed.
Japanese Patent Application Laid-Open No. 2-161431 discloses a photosensitive material processing apparatus equipped with a cover which can substantially close the spaces at the upper portions of processing tanks. Further, Japanese Patent Application Laid-Open No. 2-162347 proposes a photosensitive material processing apparatus having a cover, which can substantially close the spaces at the upper portions of processing tanks, and a means for preventing drops of solution from falling downward which has a specific configuration.
Further, U.S. Pat. No. 5,043,756 (Takabayashi et al.) discloses an automatic developing apparatus having a processing tank which is tube-shaped so that processing agents do not contact the air. Because the tank is tube-shaped and includes a small amount of the processing agent, it is necessary to completely cut off the processing agent from the air. Therefore, the structure of the apparatus is complicated, and maintenance thereof is difficult.
Because the spaces closed by the above-mentioned closing cover are larger than the exposed liquid surface, portions of the spaces which are near to the liquid surface are very humid, and the humidity of the portions decreases as the portions are distanced from the liquid surface. The moisture in the processing solutions adhering to the wall surfaces and the like evaporates, and the processing chemicals crystallize. The crystallized processing chemicals adhere to the photosensitive material which transports these crystallized processing chemicals into other processing tanks as processing continues. Such conventional closing covers have therefore been unable to prevent contamination of the processing solutions in other processing tanks.